Closed Loop

The Closed Loop feature permits the perfect synchronization between motor rotor and stator, so the motor doesn’t lose steps. This optimizes motor efficiency because only essential current is supplied. For the motor feedback feature, it’s necessary to have a feedback sensor directly on the rear shaft of a double shaft motor.

About an ‘Open Loop’ controller:

  • Reliable positioning without synchronization loss

  • Keeps the original position stable and recovers it automatically in case of positioning errors caused by external factors such as mechanical vibrations

  • 100% use of the motor torque

  • Capacity to operate at high velocity related to the current control, which is adjusted depending on the load variation. Normal systems in open loop use a constant current control at all velocities without considering the load variations.

To enable Closed Loop mode:

Related objects

Object name

Note

Motor_Parameters (Motor_Pole_Pairs)

Motor_Parameters (Motor_Step_Angle)

Min_Current

Keeps the motor in torque when the closed loop is disabled. For example, at switch-on or when the Feedback Error Alarm happens.

Nominal_Current

Motor_R

The values can be omitted if the automatic motor parameters detection is enabled. (bit9 of Drive_Working_Settings_Extended obj)

Motor_L

Drive_Working_Settings

Drive_Working_Settings_Extended

Feedback_Enc_PPR

Feedback_Kp

Feedback_Kv

Feedback_Ki

Feedback_Ki_Limit

Feedback_Kalfas

Feedback_Encoder_Filter_Time

Feedback_Kffw_Acc

Feedback_Kffw_Dec

Feedback_Kfbw_Acc

Feedback_Kfbw_Dec

Feedback_Iq_min

Feedback_Iq_Min_Threshold

Feedback_Boost_Current

Feedback_Current_Filter_Time

Feedback_Position_Error_Limit

Feedback_Calibration_Speed

Feedback_Limit_Speed

Feedback_Calibration_Current

Feedback_Velocity_Error_Limit

Feedback_Settings

Feedback_Status

Feedback_Actual_Position_Error

Feedback_Actual_Velocity_Error

Target_Torque

Max_Torque

Torque_slope

Torque_demand

Torque_actual_value

I2T_Peak_Current

I2T_TMax_Peak_Current

I2T_Current_Limit

I2T_Current_Actual

Hall_Sensors_Sequence_Settings

Hall_Sensors_Sequence_Detected

Hall_Sensors_Status

Hall_Sensors_Position

BiSS_Encoder_Config